Well plug



Nov. 21, 1939.

WELL -PLUG 2 Sheets-Sheet 1 Filed April 14, 1938 H. C. OTIS WELL PLUG Nov. 21, 1939.

Filed April 14, 1938 2 Sheets-Sheet 2 Patented Nov. 21,, 1939 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to new and useful improvements in well plugs.

One object of the invention is to provide an improved plug, insertable within a well tubing,

for closing or plugging the same during lowering of the tubing into the well bore, or during other well operations.

An important object of the invention is to provide an improved plug for a well tubing which is arranged to be disposed in sealing position within the bore of the tubing to close the flow through the tubing, said plug being constructed so that it may be displaced from its sealing position by a pressure from above, whereby the bore of the tubing may be readily opened, when desired, to permit a flow therethrough.

Another object of the invention is to provide an improved tubing plug insertable within the bore of a well tubing and having elastic packing means for sealing off between the plug and tubing bore to positively prevent leakage past the plug; the elastic packing means also providing a frictional means for holding the plug in its sealing position,

- through the tubing; said plug being provided with means, engageable by a lifting tool, whereby the plug may be again raised to its seated position so as to close the well tubing during pulling of the well tubing, or other subsequent well operations.

A further object of the invention is to provide an improved tubing plug having a metallic seating surface for engaging a seat within a well tubing and also having elastic packing means for sealing oif between the plug and tubing, whereby said packing forms a seal'in addition to the metallic seat to positively prevent leakage; said plug being constructed so that means for positively holding the plug in said sealing position may be employed to prevent accidental or unintentional displacement of the plug.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in

. as will be explained.

which an example 01' the invention is shown, and wherein:

Figure 1 is a view, partly in elevation and partly in section, of the lower end of a well tubing having a plug, constructed in accordance with the invention, in a sealing position within the tubing,

Figure 2 is an enlarged transverse, vertical, sectional view of said plug in sealing position,

Figure 3 is an enlarged horizontal, cross-sectional view, taken on the line 3-3 of Figure 1,

Figure 8 is a view, partly in section and partly in elevation, showing a particular method of holding the plug in its sealing position.

In the drawings, the numeral Ill designates the usual well tubing which extends axially through the well bore. lower end of the tubing by means of a coupling collar l2, while a second coupling collar l3 co'nnects the lower end of thesleeve with the upper end of a perforated nipple or section of tubing or pipe l4. It is preferable, although not essential, that the lower end of the perforated nipple 'or A sleeve H is connected to the" section be closed by a suitable plug l5, whereby the well fluid flows through the perforations l6 into said nipple and then upwardly through the bore III of the well tubing l0. It is noted that although the perforated nipple I4 is shown as connected to the lower end of the tubing, said nipple may be connected at any desired point in the tubing string.

The lower portion of the bore ll' of the sleeve II is preferably less than, although it may be of substantially the same diameter as, the bore of the perforated nipple and tubing, and the upper portion of ,said bore I l' is reduced, whereby an internal, annular seat or shoulder I1 is provided within the sleeve. This seat or shoulder is, preferably, bevelled or inclined, as clearly shown in Figure 2, and acts as a stop to limit the upward movement of a well plug A which is normally located within the sleeve H below said shoulder,

The well plug A includes a cylindrical body or mandrel 20 which is .formed with an external,

annular flange 2| at its lower end, preferably made integral therewith. The external diameter of the flange is slightly less than the diameter of the bore ll' of the sleeve so as to provide a slight clearance therebetween. The mandrel may be hollowed or drilled out, as shown at 20', so as-to lighten or reduce the weight of thesame. 5 A cup ring or spacer collar 22 surrounds the mandrel 20, being supported upon the flange 2| and an annular inverted packing member or cup 23 also surrounds the mandreL resting upon the dished upper end of the cupfring. .The packing cup is constructed of an elastic or flexible material, such as leather, rubber, rubber compound, or other flexible material, and is formed with an annular skirt 23'. The skirt of the packing cup depends downwardly so as to surround the upper portion of the cup ring and is spaced from said ring, whereby an annular spaceis formed therebetween. The external. diameter ofthe packing member or cup is substantially'equal to the bore ll of the sleeve ll, so that the outer surface of saidcup engages the bore of the sleeve.

A spacer ring 24 surrounds the mandrel and rests upon the packing cup 23 so as to support an upper packing cup which is disposed above said ring. The cup 25 is constructed in substantially 25 the same manner as is the cup '23. An inverted upper cup ring or spacer collar 26 surrounds the mandrel'and is -supported in said packing cup 25. An annular cap 21 is threaded onto the upper end of the i'nandrel, with 'its lower end ena ng the upper end of, the cup ring 26. With such arrangement; the packing cups 23 and 25,

cup rings 22 and 26 and the spacer ring -24 are confined on the mandrel between the flange 2| .and the cap 21. The spacer ring 24 not only serves to space the cups 23 and 25 from each other but also acts as a support for said cups to reinforce their adjacent peripheral edge portions.

However, if desired, the ring 24 may be eliminated.

The peripheral portion of the upper end of the cap 21 is bevelled at 28 and this bevel is complementary to the bevel, or incline, of the seat-or shoulder l1 formed within'the bore of the sleeve ll, whereby the cap may seat against said be engaged therewith. The neck may be drilled out or bored, as shown at 28' to reduce its weight.

. In using the plug-A, said plug is inserted within the sleeve I l and is moved upwardly therein until the bevel 28 on the cap 21 engages the annular, bevelled seat i1 within the bore of the sleeve. It is noted that theseat and bevel may be ground so as .to provide a substantially leak-proof joint,

but this is not essential. When the plug is moved upwardly-into engagement with the seat H, the packing cups 23 and 25 frictionally engage the wall of the bore H of the sleeve, and' this frictional engagement is sufficient to hold the plug in its upper position. After the plug has been positioned within the sleeve II, the perforated section of tubing or nipple I4 is coupled thereto. The sleeve is, of course, connected to the lower end of the tubing l0.

The tubing is then lowered into the well bore and the frictional engagement of the packing cups 23 and 25 is sufficient to prevent the weight of the plug from causing it to fall downwardly by gravity. As the tubing moves downwardly through the well bore, any well pressure within said bore will act against the lower nd Of t eplug to insure its remaining seated. This pressure will also be trapped beneath the skirt 23' of the lower packing cup and will expand said cup into positive sealing engagement with the well bore, whereby leakage past the plug is prevented. Since the packing cup 23 provides a positive seal, it is manifest that the metallic seat I! need not be ground to form a leak-proof joint, in which instance, said seat merely functions as a stop shoulder. If desired, the seat may be ground,

' whereby a double seal 'is had.

, be readily moved downwardly through the sleeve l I and perforated nipple l4 to the position shown 'in dotted lines in Figure 1, which is below the perforations [6. Since the bore of the nipple l4 and the bore of the well tubing I0 is preferably slightly larger than the bore I l of the sleeve II, the plug can freely fall through the nipple after displacement from the sleeve bore. It is pointed out that if desired the upper cup 25 may be eliminated, as sufficient pressure can be exerted against the top of the plug to lower the same and even though some pressure might by-pass the plug, this would not prevent downward movement of said plug; however, through the use of the cup 25, more positive lowering of the plug with less fluid volume and pressure may be accomplished. In its lowered position, the plug does not interfere with the flow of well fluid upwardly through the tubing and said plug remains in this lowered position until lifted, as will be explained.

vIt is noted that although it is desirable to lower the plug from its sealing position by means of a fluid pressure from above, said plug could be lowered by dropping a weight thereon and forcing said plug downwardly. Also, it is preferable to close the lower end of the perforated section of pipe or tubing l4, but, if desired, the lower end of said pipe could be open to allow the plug A to 'fall into the bottom of the well bore, in which case it would be possible to eliminate the perfora- 'tions IS in said pipe; or a suitable stop (not shown) could be provided in the lower portion of the nipple or section 14 to prevent the plug A from falling from the same. So long as the plug moves below the inlet perforations, or openings l6, said plug does not interfere with the flow upwardly through the tubing III.

The plugA remains in its lowered position until it is desired to again close the bore of the tubing to prevent flow therethrough. Various well operations, such as pulling the tubing or changing its position in the well bore, may require that the bore of the tubing be again plugged or closed. To efiect such closure, a suitable lifting initial position within the sleeve II, with its cap 21 engaging the bevelled seat H. The peripheral edges of the skirts of the packing cups 23 and 25 are preferably'bevelled or inclined to facilitate the insertion and removal of the cups in the 2,180,605 sleeve The-peripheries of the packing cups 23 and 25 frictionally engage the wall of the sleeve bore 2| to hold the plug in such raised position. Any well pressure below the plug further aids in holding the plug in this position and also expands the lower cup 23 to assure a fluidtight seal. The lifting tool (not shown) is then disengaged and removed, and the plug effectively closes the bore of the well tubing to prevent an upward flow therethrough. With -the tubing plugged, any well operations may be performed and when completed, the plug A may again be lowered, as explained.

In Figures 4 and 5, amodified form of the invention is shown wherein a sleeve ||a has its bore reduced at its lower portion and provided with an annular bevelled seat 35 at its lower end.

A plug B, insertable within the sleeve, includes a mandrel 36 having an external annular flange 31 intermediate its ends. An inverted packing cup 23a, similar to the cup 23, surrounds the mandrel and abuts the underside of the flange. A cup ring or spacer collar 22' also surrounds the mandrel within the cup and an inverted cap 38 is threaded onto the lower reduced and screwthreaded end of the mandrel to retain the cup ring and cup thereon. The lower end of the cap has an external annular flange 39 which is adapted to engage the seat 35 to limit upward movement of the plug B within the sleeve. neck 29', having a conical head 30', is preferably made integral with the mandrel 36 and extends upwardly therefrom, whereby a lifting tool (not shown) may be utilized to raise the plug.

When the plug B is within the sleeve with the flange 39 engaging the seat 35, the packing cup 23a is in frictional engagement with the wall of the sleeve bore. Any well pressure, which may be present below the plug, will expand the cup to increase this frictional engagement and assure a positive seal. It is possible that, in some instances, the frictional engagement of the cup 23a may be lessened to the extent that the plug B may accidentally fall to the lower end of the well tubing string. To positively hold the plug in a raised position, the cap member 38 is formed with an annular groove 40, which receives a flexible or spring ring 4|. The inherent flexibility of the ring causes it to normally project from the groove 40. When the plug .3 is within the sleeve I la, the ring 4| is adapted to engage within an annular recess,or groove 42 formed within the sleeve I la and when so engaged, the ring 4| must be moved inwardly under its own tension before the plug B can be moved downwardly. Thus, the spring tension of the ring is added to the frictional engagement of the cup 230., to insure the plug remaining in its raised position. The plug B is operated in the same manner as the plug A, hereinbefore described.

It is noted that the flange 39 on the cap 38 of the plug B is not shown as bevelled compleportion 45 having its lower portion enlarged as shown at 46, An annular, bevelled shoulder 41 is formed between the enlarged portion 46 and the upper portion of the body and is adapted to A shank or engage the seat 35 at the lower end of the sleeve. A neck 29a and head 30a, similar tothe necks 29 and 29' and heads 30 and 30 of the other forms, extend upwardly from the body.

The body is provided with an annular groove or recess 48 which receives a ring 49 of hydraulic packing or other similar material. The ring is held within the groove by vertical pins 50 and the outer periphery of said ring projects slightly beyond the periphery of the body, whereby it is adapted to frictionally engage the wall of the bore of the sleeve Ila. This frictional engagement is suflicient to hold the plug within the sleeve. The ring thus holds the shoulder 41 engaged with the seat 35 and this engagement of said shoulder with said seat provides a fluid-tight seal. The ring also aids, to some extent, in preventing leakage. The operation of this form is exactly the same as the other forms.

In the event that the ring 49 of hydraulic packing is not suiflcient to maintain the plug C in'a raised position, the spring ring 4| and grooves 40 and 42 could be provided; or in place of said ring 4|, the neck 29a may be formed with a transverse opening (Figures 6 and 8), whereby one end of a wire 52 may be tied to the neck. The other end of the wire is fastened to a nail, or other relatively small member 53, which extends transversely of the well tubing, and which has its ends confined between the first coupled joint above the plug. The member 53 may be frangible or flexible to the extent that it may be dislodged from its position. With this arrangement, the plug C is positively held in a raised position by the wire 52 and member 53 and remains so until a pressure from above is exerted on the plug. Such pressure causes the member to bend or break which pulls its ends from the coupled joint and thereby permits the plug C to move downwardly. Obviously, this method of positively holding the plug in a raised position could be used with either of the other plugs A and B.

The plugs have been shown as movable into a sleeve which is formed with an internal seat or shoulder, but said sleeve could be entirely eliminated with the seat being formed within the well tubing Ill. The use of the sleeve, however, makes forconvenience in manufacture and connection of the device at a desired position in a well tubing string.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape' and materials, as well as in the details of the illustrated construction may be made, withinthe scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A wellplug device including, a tubular section arranged to be connected in a well tubing string and having a stop, and a plug movable in v saidsection downwardly from and upwardly to said. topgand having means engageable with said section and releasable under pressure for holding said plug in position against said stop.

2. The combination with a tubing string having a fluid iniet and a stop above said inlet, of a flow obstructing plug movable in said string to a point below said inlet to admit fluid to said string and to permit free flow up said tubing string and movable to said stop to obstruct flow up said tubing, and means on said plug coactlng with said tubing string for holding said plug in its obstructing position.

3. A well plug for a well tubing string including, a support having a seat adapted to coact with a stop element in the tubing string, and an elastic packing member on the support and arranged to frictionally engage the tubing wall to seal ofi between the support and tubing and also for holding said support in a position with its seat engaging the stop element.

4. A well plug for a well tubing string including, a mandrel movable in the tubing string, said mandrel being arranged to engage a stop element formed within said tubing string, a pair of annular elastic packing elements mounted one above the other on said mandrel and having frictional engagement with the tubing wall to seal ofl between the mandrel and tubing and also to hold the mandrel in a raisedposition against the stop element, said packing members being so constructed that pressure from above the mandrel distorts one of said members into positive sealing engagement while a pressure from below distorts the other member.

5. A plug for a well tubing string having a stop element within its bore including, a body movable within the bore of the tubing and adapted to coact with the stop element to limit upward movement of said body in the bore, an annular packing member on the body adapted to engage the tubing wall to seal ofi between the body and tubing, and resilient means on the body for normally holding the body in a raised position.

6. A plug for a well tubing string having a stop element within its bore including, a body movable within the bore of the tubing and adapted to coact with the stop element to limit upward movement of said body in the bore, an annular packing member on the body adapted to engage the tubing wall to seal off between the body and tubing, and retractible means connecting the 'body and tubing when the body is in a raised position, whereby said body is positively held in such position, said means being retractlble by a pressure from above the body.

'7. The combination with a well tubing string having a fluid inlet and a stop element above said inlet, of a flow obstructing plug movable in the string to a point below the inlet to permit free flow of fluid through said inlet and upwardly through the string and also being movable into engagement with the stop to obstruct flow upwardly through the tubing, and means attached to the upper end of the plug and to the tubing above said plug for holding said plug in its obstructing position, said means being displaceable under pressure when sumcient pressure is exerted against the upper end of the plug to permit the plug to move downwardly in the tubing.

8. A well tubing plug having an annular seat for engaging a complementary seat in a tubing section to form a seal between said plug and tubing, and flexible means on the plug having frictional engagement with the tubing wall for holding the plug in its seated position.

9. A well tubing sealing plug including a body having an annular stop for engaging a seat in a tubing and a circumferential recess, an annular flexible packing member engaging in the recess of said body and arranged to engage a tubing wall, and a neck connected with the upper end of the body for receiving a lifting tool.

10. The combination with a tubing stringhaving a fluid inlet and a stop above said inlet, of a flow obstructing plug movable in said strin to a point below said inlet to admit fluid to said string and to permit free flow up said tubing string and movable to said stop to obstruct flow up said tubing, and means on said plug frictionally coacting with said tubing string for holding said plug in its obstructing position.

HERBERT C. OTIS. 

